The Hatschek process for the production of fiber cement sheets is well known in the art. Typically, a number of fiber cement monolayers are created by means of successively installed rotating sieve drums. The layers are picked up and stacked on an endless water-permeable transport belt so as to form a fiber cement multilayered slab. The multilayered slab, which is transported in the production direction, is subsequently contacted by a rotating accumulator roll, which ensures the accumulation of a plurality of fiber cement multilayered slabs. After reaching a predefined thickness, the resulting fiber cement sheet is cut, taken from the roll, and put on a transport device. The fiber cement sheet is subsequently optionally processed and cured in a suitable way to obtain the finished end product.
The resulting fiber cement products, however, typically have performance drawbacks relating to resistance to water induced damages, water permeability, water migration ability (also known as wicking) and freeze thaw resistance. These drawbacks are largely due to the presence of pore spaces and water conducting channels within and in between the fibers of the cementitious matrix. The porosity of fiber cement products facilitates water transportation throughout the composite materials and can affect the long-term durability and performance of the material in certain environments.
To counter the above indicated drawbacks, the outer surface of a finished fiber cement product is sometimes coated with one or more layers of a coating agent. However, only a small crack or minor damage of the coating outer layer of the product is already sufficient for allowing water to trickle into the fiber cement mass, thereby undoing the products water-impermeable properties.
Accordingly, there remains a need for an efficient method for preventing damage and degradation to a fiber cement building material, particularly due to water and/or other environmental effects. In addition, there is a need for improved material formulations and products having an increased resistance to water and/or environmental degradation.